by Susan Page, USA TODAY

by Susan Page, USA TODAY

WASHINGTON -- President Obama had just signed an executive order barring discrimination by federal contractors against gay and transgender employees to an East Room audience that greeted his comments with cheers and applause. "We've got the 'Amen!' corner here," he declared to laughter.

Moments later, he walked out to the South Lawn for sober remarks to reporters on the crises in Ukraine and the Middle East.

No cheers this time.

The pair of events illustrate the second-term issues that Obama now faces. On domestic policy, he's been forced to turn to executive orders â?? limited in their impact and subject to repeal by the next president â?? because passing legislation in Congress has proved problematic even on such top-tier issues as immigration and veterans' health care.

And on foreign policy, he seems buffeted by challenges beyond his control in every corner of the world: The shootdown of the Malaysian jetliner in Ukraine, apparently by Russian-backed insurgents. The deadly Israeli invasion of Gaza, with horrific TV footage showing the deaths of women, children, an ambulance driver, a news reporter. The rising al-Qaeda-like insurgency in Iraq and Syria. The turmoil in Central America that is one factor in the flood of children crossing the southern U.S. border.

He spoke with caution. His language was a bit more circumspect than that Secretary of State John Kerry had used in appearances on the Sunday morning TV interview shows 24 hours earlier. Obama said that Russia was known to have provided arms, including anti-aircraft weapons, to the separatists.

He also offered only indirect threats of what he might do next. "My preference continues to be finding a diplomatic resolution in Ukraine," he said, "but if Russia continues to violate Ukraine's sovereignty and to back these separatists...then Russia will only further isolate itself from the international community and the costs for Russia's behavior will only continue to increase."

He didn't specify what those costs might be, and he didn't demand that European allies that have been reluctant to impose tougher economic sanctions against Moscow do so now.

Obama may be in step with American public opinion in holding his fire for now. A poll by POLITICO taken before the shootdown found that just 17% thought the United States should do more to counter Russian aggression in Ukraine. A third said the U.S. should be less involved. By wide margins, those surveyed opposed more engagement in Iraq, Afghanistan and Syria.

At the same time, however, Americans were inclined to trust Republicans over Democrats when it came to handling foreign policy, 39% to 32%. The Pew Research Center and other national polls have shown Obama's approval rating on foreign policy, once a strong point, falling to the mid-30s.

Those surveys were taken before the latest crises.

The White House so far hasn't changed Obama's public schedule to deal with events â?? even last Thursday, the day the plane was shot down over Ukraine and Israeli ground troops moved into Gaza. Obama went ahead with lunch at a diner in Delaware and political fundraisers in New York.

On Monday, too, he kept to his schedule. After making remarks to reporters, he ignored shouted questions and boarded the presidential limousine for the drive to a Washington school. There, he was spotlighting a White House initiative called My Brother's Keeper, designed to help at-risk African-American and Hispanic boys and young men.